<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
 
</head>

<body>
  <div id="app">
    <button @click="addArr">新增数组</button>
    <ul>
      <li v-for="item in arr" :key="item">
        {{item}}
      </li>
    </ul>
  </div>
  <script src="./vue.global.js"></script>
  <script>
    const { createApp } = Vue;
    const app = createApp({
      data() {
        return {
          arr: [1,2,3,4]
        }
      },
      methods: {
        addArr() {
          this.arr.push(this.arr.length+1);
          this.$nextTick(() => {
            // 回调会在 当前数据修改后视图刷新完成后触发
            console.log(document.querySelectorAll('li'), 222);
          })
          console.log(document.querySelectorAll('li'), 111);
        }
      },
    })
    app.mount('#app')
  </script>
</body>

</html>